Help/prop_tgt/WINDOWS_EXPORT_ALL_SYMBOLS.rst

WINDOWS_EXPORT_ALL_SYMBOLS
--------------------------

This property is implemented only for MS-compatible tools on Windows.

Enable this boolean property to automatically create a module definition
(``.def``) file with all global symbols found in the input ``.obj`` files
for a ``SHARED`` library (or executable with :prop_tgt:`ENABLE_EXPORTS`)
on Windows.  The module definition file will be passed to the linker
causing all symbols to be exported from the ``.dll``.
For global *data* symbols, ``__declspec(dllimport)`` must still be used when
compiling against the code in the ``.dll``.  All other function symbols will
be automatically exported and imported by callers.  This simplifies porting
projects to Windows by reducing the need for explicit ``dllexport`` markup,
even in ``C++`` classes.

When this property is enabled, zero or more ``.def`` files may also be
specified as source files of the target.  The exports named by these files
will be merged with those detected from the object files to generate a
single module definition file to be passed to the linker.  This can be
used to export symbols from a ``.dll`` that are not in any of its object
files but are added by the linker from dependencies (e.g. ``msvcrt.lib``).

This property is initialized by the value of
the :variable:`CMAKE_WINDOWS_EXPORT_ALL_SYMBOLS` variable if it is set
when a target is created.